<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <script>
        const arr=[1,3,4,5,66,66,7,74];
        const arrs=[
            {title:'nashibao',price:75},
            {title:'nashibaos',price:175},
            {title:'nashibasoss',price:735},
            {title:'nashibaosfsfa',price:475},
        ]
        // var res=arr.map(item=>item*2);
        // let res=arr.map(item=>item>10?'jige':'bujige')
        // let res=arr.reduce((tmp,item,index)=>{
        //     if(arr.length-1!=index){
        //         return tmp,item;
        //     }else{
        //         return (tmp+item)/arr.length;
        //     }
        // })

        // let res=arrs.filter(item=>item.price>300)

            let res=arr.forEach((item,index)=>{
                console.log(item+':'+index)
            })
        console.log(res)
    </script>
</body>
</html>